False twisting method and apparatus



Feb. 17, 1970 DJCUMW N ETAL 3,495,390

FALSE TWISTING METHOD m) APPARATUS Filed a 20, 1968 v 2 Sheets-Sheet 1 imulfiiilimlilillllliihni YARN PATH INVENTORS JAMES D- CUMMINGS I I 3.1T $25422 W BY flame.

A TTORNE Y Feb. 17, 1970 J. p. CUMMlNGs EI'AL 3,495,390

7 v FALSE twiswme unmon AND APPARATUS Filed June 20. 1968 2 Sheets- Sheet 2 INVENTORS JAMES B. CUMMINGS A.HAROLD GIBBS y BILLY SEAR ATTORNEY United States Patent 3,495,390 FALSE TWISTING METHOD AND APPARATUS James D. Cummings, Arthur Harold Gibbs, and Billy L. Sears, Greensboro, N.C., assignors to J. P. Stevens & Co., Inc., New York, N.Y., a corporation of Delaware Filed June 20, 1968, Ser. No. 738,447 Int. Cl. D01h 13/26 US. CI. 57-34 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method for crimping a yarn by false twisting and comprises the steps of rotatably positioning at least one mandrel so that its axis is maintained at a predetermined angle with the path of the yarn passing thereover. By permitting the yarn to be slidingly wrapped around said angled mandrel, the yarn causes the mandrel to rotate and to impart a twist which is then heat-set when the twist is backed up over a setting heater positioned prior to the angled mandrel, whereby a torque crimped yarn having substantially no change in actual twist is produced.

This invention relates generally to a method and apparatus for false twisting running yarn. In one aspect it I relates to a method and apparatus to which false twist is imparted to the yarn by causing it to be slidingly wrapped around a rapidly rotating member, said member rotating around an axis which is positioned at a specified angle in relation to the path of the running yarn.

It is known that a false twist can be imparted to a running yarn by causing it to be rotated along its axis using various types of false twist spindles. False twist is often applied to crimping filament yarns wherein the yarn is subjected to a setting treatment while in a state of high twist. Although the yarn, after passing through the false twisting device, returns to an untwisted state, it retains a tendency to crimp as a result of the setting treatment.

With known methods and apparatus the obstacle which has always limited simplification in speeding up of production and reduction in cost thereof is the problem of supporting the rapidly rotating member. The member must be supported both radially and axially.

All of the prior art methods are either costly or do not always permit the high speeds desired. Moreover even if high speeds are attained the apparatus wears out extremely fast.

Therefore it is one object of this invention to provide a false twisting method which is extremely simple and inexpensive in combination and requires little power and can be easily maintained.

It is another object of this invention to provide a method which is capable of providing high speeds and is simple to operate;

Yet another object of this invention is to provide an apparatus for false twisting yarn that will permit high production speeds and is not expensive to operate;

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description which is to be considered in connection with the accompanying drawings wherein:

FIG. 1 represents a schematic view showing the course pursued by the yarn in undergoing the process of the present invention, and

FIG. 2 represents a perspective view of one means for rotatably supporting the mandrel with its axis in a predetermined angle with relation to the path of the yarn;

FIG. 3 represents a schematic view showing a preferred embodiment of the course pursued by the yarn in undergoing the process of the present invention.

Briefly this invention comprises a method for crimping a yarn, wherein it comprises the steps of rotatably positioning at least one mandrel the axis of which is at a predetermined angle with the path of said yarn passing to the mandrel; permitting the yarn to be slidingly Wrapped around said mandrel; maintaining a sufiicient tension on said yarn to cause a twist backup over a setting heater positioned prior to said angled mandrel and winding the torque crimped yarn onto a suitable take-up device.

In the operation illustrated in FIG. 1, a yarn 1 passes from a yarn supply package 3, through a yarn guide means 5, over a tension compensating means 7 through a heater 9, and is slidingly wrapped around a mandrel 11 which is rotatably supported by a suitable means 12.

The support means 12 described in more detail herein below is capable of supporting the mandrel so that its axis of rotation is maintained at an angle 0 with respect to the path of the traveling yarn as it approaches the mandrel. This angle 6 ranges from 10 to preferably 35 to 55. By so positioning the mandrel, the yarn is capable of rotating the mandrel without the need for any external power.

A tension is maintained on the yarn in order to cause a twist backup over heater 9 which is then heat-set.

The yarn then passes through a pair of feed rolls 15 and 17 onto a take-up spool 19.

A suitable supporting means 12 capable of adjusting the angle 0 is shown in FIG. 2. The mandrel 11 is supported by two small bearings (not shown) so as to be rotatably mounted onto shaft 21. Shaft 21 is frictionheld to member 23 by conventional locknut 25. Member 23 is adjustably supported onto a stationary member 27 by locknut 29. In order to change the angle of shaft 21 the locknuts 25 and 29 are loosened to permit shaft 21 and member 23 to be positioned into the proper angle relationship with the path of the yarn.

It has been unexpectedly discovered that by the proper setting of the tension of the yarn being fed to mandrel 11 in conjunction with the yarn take-up speed that a twist backup can be produced over the setting heater 9. Because of the positioning of the rotating shaft 21 of mandrel 11 at the angle 0 in relation to the path of the yarn traveling toward said mandrel, the yarn is caused to roll and slip along the surface of the mandrel which rolling action inserts twist into the yarn which is then heat-set as the twist backs up over the heater.

It is to be noted that if 0 is reversed, an opposite twist yarn will result in the heat zone from that produced with the mandrel positioned as described hereinabove but that the resulting yarn will still have a zero twist therein.

The tension of the yarn being fed to the mandrel 11 ranges from 0.001 to 6 grams/denier preferably 0.25 to 1.5 grams/ denier and suflicient tension is maintained on the wind-up roll to effect a desired package depending on the end use desired for the yarn. The denier of the yarn is not critical to the operation of this invention and can be selected according to the particular desires of the end use.

The temperature in the heating zone should be as high as possible without the danger of any deterioration of the textile fibers occurring therein. Heater temperatures have been found to be satisfactory ranging from 350 to 600 F. The speed at which the yarn passes through the heat zone 9 and the highest temperature which the yarn can withstand both depend on the nature of the yarn on which the process is carried into effect. The system has no real limit on speed except for the requirement of a high speed winder 19. Results have been obtained with yarn speeds ranging from 50 to as high as 3000 yards per minute.

A textile product in accordance with this invention can be manufactured from a wide variety of materials. For example, the textile product may be proteinaceous material, cellulosic material, synthetic thermoplastic polymeric material, thermosetting polymeric material and the like. Illustrative of such materials are the cellulosic fibers, cellulosic acetate fibers, polyarnides, polyesters, acrylics, wool, cotton and the like.

In a specific application, as shown in FIG. 3, embodying the principles of this invention, a 15/3 filament Nylon 66 (polyhexamethylene adipamide) yarn 31 was passed over a GE magnetic brake, which was employed as the tension compensating means 33, under a tension of 7 grams through the heater 35 at a temperature of 455 F. The length of the heater assembly was maintained at 39 inches. The yarn was passed over 3 one-half inch diameter mandrels 37, 39 and 41 all of which were rotatably positioned on a support means 12 which is similar in construction to that described hereinabove wherein the axis of each mandrel is friction-held at an angle of 45 with relation to the path traveled by the yarn as it approaches each mandrel. The yarn in wrapping around the mandrels caused them to rotate without the need for any additional external power. Mandrels 37, 39 and 41 were all constructed of aluminum provided with a matte finish. The yarn was then passed through the feed rolls 43 and onto winder 45 under a wind-up tension of 2 grams. This yarn was processed at the rate of 2200 yards per minute and contained 120 turns per inch of false twist.

When this result is compared with a conventional false twist spindle (at 120 turns per inch) a spindle speed of 7 million r.p.m.s would have to be employed to obtain the same result. The best commercial false twist spindle units to date operate between 400,000 and 600,000 r.p.m.s or less than one-tenth the speed of the subject process.

It can be readily seen that this false twist texturizing process and apparatus offers exceptional advance over the prior art.

What is claimed is:

1. A process for crimping yarn comprising (a) pulling said yarn downstream from a source of supply in a path leading to a takeup device,

(b) at a point intermediate the source of supply and the takeup device, passing said yarn while under tension around a plurality of rotatably mounted mandrels so that movement of the yarn along said path causes said mandrels to rotate, the axes of all said mandrels being at about the same predetermined angle in relation to the path of the yarn as it approaches the respective mandrels, said angle being within the range of 10 to 80, the passage of the yarn around said mandrel causing said yarn to back up from said mandrels in a twisted state in a region extending back toward the source of supply and (c) applying heat to said yarn within the region of twist backup.

2. A process as claimed in claim 1 wherein said yarn is made of a thermoplastic material.

3. A process as claimed in claim 1 wherein said yarn is made of polyhexamethylene adipamide.

4. A process as claimed in claim 2 wherein a tension of 0.001 to 6 grams per denier is applied to said yarn at a point upstream to the point at which said yarn is heated.

5. A process as claimed in claim 2 wherein three rotatably mounted mandrels are employed.

6. A process as claimed in claim 2 wherein the angles between the axes of the mandrels and the path of the yarn approaching the respective mandrels .is about 45.

7. A process as claimed in claim 6 wherein said yarn is a 15 denier, 3 filament polyhexamethylene adipamide yarn, three rotatably mounted mandrels are employed and the tension on said yarn prior to its passing around the first of said mandrels is maintained at 2 grams per denier.

8. A texturing apparatus capable of forming a torque crimp yarn having substantially no change in actual twist, said apparatus comprising (a) a yarn supply means,

(b) means for pulling said yarn along a predetermined path leading from said yarn supply means to a yarn wind-up means,

(c) a plurality of rotatable mandrels for imparting false-twist to said yarn positioned along said path, said mandrels being mounted so that during operation of the apparatus they can be set in a position wherein the axis of each mandrel is at an angle of 10 to with respect to the path of the yarn approaching the mandrel,

(d) yarn heating means positioned along said path at a point upstream from said mandrels, and

(e) tension control means positioned along said path at a point upstream from said heating means.

9. An apparatus as claimed in claim 8 which has three rotatable mandrels, all set so that their axes are at about the same angle with respect to the path of the yarn approaching the mandrels.

10. An apparatus as claimed in claim 8 wherein said apparatus includes adjustable support means for said mandrels whereby the angles between the mandrel axes and the path of the yarn approaching the mandrels can be changed.

References Cited UNITED STATES PATENTS 3,422,613 1/1969 Berger et al. 5734 2,988,867 6/1961 Quittner 57-55.5 XR 2,991,614 7/1961 Ubbelohde 57-34 3,026,668 3/ 1962 Latimer 57-77.4 3,114,999 12/1963 Coggeshall 57-55.5 3,327,461 6/1967 Wyatt 57-77.4 XR 3,386,143 6/1968 Van Silfhout 57-34 XR DONALD E. WATKINS, Primary Examiner U.S. Cl. X.R. 57-77.3, 156 

